Preparation and biodistribution study of [67]Ga-gallium calcitonin

ABSTRACT

In order to develop a radiolabeled calcitonin [CT] derivative for receptor imaging studies, CT was successively labeled with [67]G-gallium chloride. The best results of the conjugation were obtained by the addition of 0.5 ml of a CT nasal pharmaceutical solution [1100 IU] to a glass tube pre-coated with DTPA-dianhydride [0.01 mg] at 25 [degree sign] with continuous mild stirring for 30 min. after solid phase purification of the radiolabeled hormone, instant thin layer chromatography [ITLC] showed radiochemical purity of higher than 95% at optimized conditions [specific activity = 67-134 KBq/IU, labeling efficiency 70%]. [67]Ga-DTPA-CT mainly accumulates in the liver. Preliminary in vivo studies [ID/g%] in male wild-type rats showed significant liver uptake of the tracer after 24 hours. [67]Ga-DTPA-CT can be a suitable probe for biodistribution study of CT receptors in various physiological as well as neoplastic lesions with over-expressed calcitonin receptors